Vertical industrial x-ray fluoroscope



July 7, 1959 Filed June 4, 1957 J. G. SCHNEEMAN VERTICAL. INDUSTRIALX-RAY FLUOROSCOPE 2 Sheets-Sheet 1 I INVENTOR. Jusmv 6. SGHNEEMAN y 7,1959 J. G. SCHNEEMAN' 2,894,140

VERTICAL INDUSTRIAL X-RAY FLUOROSCOPE Filed June 4, 1957 2 Sheets-Sheet2 uvwszvrox Jusrl/v 6 Sc/INEEMAN 4270mm vs United States Patent VERTICALINDUSTRIAL X-RAY FLUOROSCOPE Justin G. Schneeman, Rivera, Calif.

Application June 4, 1957, Serial No. 663,427

4 Claims. (Cl. 250-62) This invention relates generally to fluoroscopicinspection apparatus, and more particularly to apparatus forfiuoroscopically inspecting. manufactured parts and assemblies.

In my Patent No. 2,683,812, issued July 13, 1954, and

entitled Fluoroscopic Inspection Apparatus, I have shown and describedapparatus which is quite well adapted for use in the usual industrialapplications of fluoroscopic inspection. This apparatus makes itpossible to inspect a part which is larger than the fluorescent screenand viewing aperture, because the part-supporting means moves the partwith respect to the screen thereby allowing the various portions of thepart to be viewed individually. At the same time, the apparatus providescomplete shielding of the part and radiation source for theprotection ofthe operating personnel.

Certain special applications have been encountered, however, withrequirements that call for apparatus having additional capabilities. Forinstance, in certain applications it is desirable that the imageproduced by the apparatus have a particularly high degree of resolution;that is, be sharp and distinct.

As is well known to those skilled in the art, the resolution of an imageis always hampered to some degree by the fact that. it is impossible, inpractice, to produce a point; source of rays, and, as a result, raysfrom one part of the source strike a given point in the specimen at aslightly different angle than rays from another part of the source. Theresolution of an image can be improved, however, by increasing thedistance between the source of radiation and the specimen, and/or bydecreasing the distance between the screen and the specimen, becausethis proportionately reduces the efiect of the angular discrepanciesbetween the rays.

Therefore, in applications where a high degree of resolutionis required,apparatus is needed which is capable of effecting a substantial spacingbetween: the source and the specimen, while, at the same time, allowingthe screen to be positioned in. close proximity to the specimen.Inspection apparatus knownand used prior tothis invention does not havesuflicient capabilities in this regard.

Furthermore, experience in fluoroscopic inspection has shown that flawsin the parts or assemblies being inspected often show up better when theX-ray beam strikes the part at a certain angle of incidence. For thisreason, it is quite advantageous, in applications where flaws areparticularly difiicult to detect, to be able to vary the angle ofincidence of the X-ray beam.

Also, special applications have arisen wherein it is necessary to.fiuoroscopically inspect very large parts or assemblies. Thisrequirement is often encountered in the aircraft industry, for instance,where wing sections and other large assemblies require inspection.Apparatus, such as that disclosed in my Patent No. 2,683,812, referredto above, which moves the part being inspected in a horizontal plane, isnot suitable for such inspection,

because horizontal movement of large parts, if contained within ashielded housing, would necessitate a housing of excessive floor spaceand make viewing by the operator through the vertically opening aperturequite diflicult.

On the other hand, if apparatus is designed which holds the specimen ina fixed position and scans it by moving the beam, provision must also bemade for moving the screen and the operator viewing it, so that theyremain in alignment with the beam. In addition, some means of shieldingmust be provided which allows such movement and still adequatelyprotects the operating personnel. As a result, apparatus of movable beamtype design is quite complicated and expensive. Suitable apparatus forthe fluoroscopic inspection of large parts is therefore not easilyachieved.

It is therefore a major object of this invention to provide fluoroscopicinspection apparatus which is capable of fulfilling all of theabove-mentioned requirements for special applications.

It is also an important object of this invention to provide fluoroscopicinspection apparatus in which the axis of the beam of radiation isgenerally horizontal and the distance between the source of radiationand the specimen being. inspected may be varied while inspection is inprogress and may be substantially increased when high image resolutionis required.

It is another object of this invention to provide inspection apparatusof the character described in which the distance between the screen andthe specimen being inspected may be varied to adjust the imagepresentation, and the radiation source may be tilted to change the angleof incidence of the beam on the specimen while inspection is inprogress.

It is a further object of this invention to provide fluoroscopicinspection apparatus of the type described above which is capable ofhandling, as specimens, large parts or assemblies, and moving thesespecimens with respect to a substantially fixed beam of radiation,while, at the same time, providing adequate protection for operatingpersonnel.

Still another object of this invention. is to provide inspectionapparatus of the type described above in which the movement of thespecimen being inspected is. poweroperated and can be controlled by theoperator from aremote operating station, while inspection is inprogress.

Still a further object of this invention is to provide inspectionapparatus as described above in which different means for producing andrecording images producedfrom the beam of radiation may be substitutedby the operator, as desired, while inspection is in progress.

And yet another object of this invention is to provide fluoroscopicinspection apparatus of the character described which has a unitaryconstruction, occupies a minimum of floor space, and is relativelyinexpensive to manufacture.

These and other objects and advantages of this invention will becomeapparent upon a consideration of the following detailed description of apreferred embodiment thereof, read in connection with the accompanying.draw ings, wherein:

Figure l is a perspective view illustrating the general form,arrangement and appearance of a preferred embodiment of this invention;

Figure 2 is a cross-sectional view taken substantially along line 22 inFigure 1;

Figure 3 is a cross-sectional View taken substantially along line 33. inFigure 1;

Figure 4 is a fragmentary cross-sectional view taken:

substantially along line 4--4 in Figure 2;

Figure 5 is a cross-sectional View taken substantially along line 5-5inFigure2;

Figure 6 is a cross-sectional view taken substantially along line 66 inFigure 3;

Figure 7 is a cross-sectional view taken substantially along line 7 7 inFigure 6; V

Figure 8 is a fragmentary side elevation of an access door containingimage-producing apparatus;

Figure 9 is a cross-sectional view taken substantially along line 9-9 inFigure 8, in which a dotted outline illustrates how the viewingapparatus may be repositioned; and

Figure 10 is a fragmentary side elevation of the inside of the accessdoor shown in Figure 8. In general, fluoroscopic inspection apparatuscontains these essential elements: a source of penetrating radiations,means for positioning the specimen to be inspected before the beam ofradiations emanating from the source, means for producing an image fromthe beam after it has intercepted the specimen, and means for protectingpersonnel from the harmful effects of the radiation.

In the disclosed embodiment of this invention, the source of thepenetrating radiations is an X-ray tube, but it could, of course, besome other suitable radiation source, such as a radioactive element orcompound. The specimen support means comprises two powerdriven carriagesadapted to move the specimen about in front of the beam of radiationemanating from the X-ray tube in a plane generally normal to the path of"the beam, so that the beam can scan all portions of the specimen. Thus,scanning of the specimen is effected in this apparatus by moving thespecimen with respect to the radiation source. The means for producingan image constitutes a fluorescent screen positioned on the oppo- !siteside of the specimen from the radiation source so that the radiationbeam will intercept the specimen before striking the screen, andtherefore produce an image of the specimen thereon, and the means forshielding the operating personnel from the radiations is a housing ofmaterial impenetrable to the radiations. Other imageproducing means arealso provided and made interchangeable with the screen, as will beexplained later. The housing completely encloses the aforementionedelements, yet, at the sarne time, makes provision for viewing of thescreen by the operator, ingress and egress of the specimens, and controlof the movement of the specimen support. Thus, all of the elementsessential to fluoroscopic inspection apparatus are present.

Referring now to the drawings, and particularly to Figure 1 thereof, thereference numeral 10 indicates generally a housing which comprises twotunnelshaped portions joined to form a T in the plan View. Thetunnelsshaped portion forming the top of the T is indicated by thereference character 11, and is referred to as the specimen tunnel, sinceit is designed to contain the part or assembly being inspected. Theportion forming the leg of the T is designated by the numeral 12 and isreferred to as the radiation tunnel, since it contains the source ofradiation.

Each of the tunnels is rectangular in cross-section and has wallsconstructed of lead and/or other material impenetrable by the type ofpenetrating radiation to be used, in this case X-rays. The specimentunnel 11 extends to the floor and is supported thereon by laterallydisposed I beams 13. Channel irons 14 run up the face wall 15 ofspecimen tunnel 11 to give additional rigidity. Since, as will becomeapparent later, the radiation beam is directed toward the face wall 15,this wall has extra thickness in order to assure adequate shielding. Anaccess door 16 containing image-producing apparatus used by the operatorduring inspection of the specimen is positioned on face wall 15 betweenthe channels 14. The door 16 provides a convenient means of access tothe central portion of the specimen tunnel 11 and is located atapproximately eye level above the floor so that the image producingapparatus is positioned at a convenient height for an operator. Theoperators station for the inspection apparatus is the general area 17 infront of the access door 16.

In the right hand end wall 18 (in Figure 1) of the spec1- men tunnel 11,a specimen portal 19 is provided. The specimen portal 19 extends overthe major portion of end wall 18 and is large enough to pass any part orassembly which specimen tunnel 11 can accommodate.

The radiation tunnel 12 is joined to the specimen tunnel 11 at theapproximate center of the specimen tunnel back wall 21 (see Figure 3)and communicates with the specimen tunnel through an opening 21a. Theradiation tunnel 12 is considerably less in height than the specimentunnel 11 and therefore only extends part way to the floor. Legs 22 areprovided to support the free end of the radiation tunnel. An access door23 is provided in one side of radiation tunnel 12 to permit ready accessto its interior.

To support a part or assembly and provlde means for moving it about forscanning by the radiation beam, the specimen tunnel 11 contains aspecimen support 24 (see Figure 2) which comprises a vertical carriage25 for moving the specimen up and down with respect to the beam and ahorizontal carriage 26 for moving the specimen back and forth. Thevertical carriage 25 extends longitudinally from one end of the tunnelto the other and has rollers 27 disposed at each end which engage androll on vertical guides 27a mounted at each end of the tunnel. (SeeFigure 4).

To provide means for raising and lowering the vertical carriage 25,vertically disposed jack screws 28 are rotatably mounted adjacent eachend of the carriage and are connected to the carriage by travel nuts 29which travel up and down on the screws. The screws 28 are driven inunison through bevel gears 30 by a horizontally disposed drive shaft 31which extends across the upper portion of specimen tunnel 12. The driveshaft 31 is rotated by a motor 32 which is also mounted in the upperportion of the specimen tunnel 12.

To counterbalance the weight of the vertical carriage 25 and thus reducethe load on motor 32, counterweights 33 are connected to the carriage bymeans of cables 34 and overhead mounted pulleys 35.

The horizontal carriage 26 of the specimen support 24, which providesfor back and forth movement of the specimen, is mounted in piggybackfashion on the vertical carriage 25 and travels longitudinally inspecimen tunnel 11. The horizontal carriage 26 travels on two rails, anupper rail 38 and a lower rail 39 (see Figure 5). The rails 38 and 39are disposed hon'zontally and in a longitudinal direction on verticalcarriage 25 with the upper rail 38 positioned approximately in thecenter of the top of the carriage and the lower rail 39 approximately inthe center of the bottom.

To engage these rails, the horizontal carriage 26 has guides 41 eachcomprising a group of three rollers. Two of the rollers 42 of the guides41 are disposed for rotation in a horizontal plane and are spaced apartjust enough to snugly receive the corresponding rail between them. Theserollers 42 are called guide rollers because they guide the movement ofthe carriage. The other roller 43 of each guide 41 is disposed to rotatein a vertical plane and position to engage a horizontal surface of therail. These rollers 43 position the carriage vertically between the tworails 38 and 39 and are called main rollers since the main rollers inguides 41 engaging lower rail 39 carry the weight of horizontal carriage26 and the specimen.

To provide means for driving the horizontal carriage 26 along the rails38 and 39, a rack gear 44 is positioned on one side of lower rail 39,and a drive motor 45, mounted on the horizontal carriage, is engagedwith this rack gear.

Since the drive motor 45 is mounted on horizontal carriage' 26 itselfand vertical and horizontal carriages 25 and 26 are movable both withrespect to each other and with respect to the housing 10, a specialarrangement is necessary to. carry electric power 'conductorsrfrom thehousing to the motor. This arrangement is provided by two spring-loadedtake-up reels 47 and 48, both mounted on the vertical carriage 25 (seeFigure 2). The electric power is carried from an outlet box 49 onhousing to the first take-up reel 47, which is mounted on the upperportion of vertical carriage 25, by a flexible electric cord 50. Thesecond take-up reel 48 is mounted on the lower portion of'verticalcarriage and connected to the first reel 47 by a solid conduit 51. Asecond flexible electric cord 52 is then used to connect from the secondreel 48 to drive motor mounted on horizontal carriage 26. Thus, asvertical carriage 25 moves with respect to outlet box 49 on the housing10, the first reel 47 pays out or takes up the flexible cord 50,asrequired, and when horizontal carriage 26 moves with respect tovertical carriage 25 and the reels 47 and 48, carrying the drive motor25 along, the second take-up reel 48 pays out or takes up the flexiblecord 52.

The two drive motors 32 and 45 which drive the two carriages of specimensupport 24 are controlled by control means mounted on face wall 15 ofthe specimen tunnel 11. The control means 55 is within easy reach of theoperatorsstation 17.

To mount a part or assembly on the specimen support 24, a fixture 56 isprovided which can be made of material substantially transparent to thepenetration of the particular radiation used, when necessary to avoidinterference with proper viewing. Certain woods, resins, or

plastics are satisfactory for this purpose. Clamps 57 are provided onfixture 56 to hold the specimen in place.

To support the radiation source in the radiation tunnel 12, ayoke-shaped support frame 60 .(see Figures 3 and 6) is longitudinallydisposed in the tunnel and pivotally mounted on trunnions 62 projectingfrom the sides thereof, adjacent the opening 21a into specimen tunnel11. The major portion of the support frame 60 comprises two parallelarms 61 which extend rearward from the mounting trunnion's 62, andslidably, carry a holder 63 which holds the X-ray tube 64.

At their distal ends the arms are connected by a crossbar 65 andsupported by a flexible cable 66 which passes through a pulley 67attached to the top of the radiation tunnel. By means of additionalpulleys 67a, the cable 66 is carried to a manual control reel (seeFigure l) on the face wall 15 adjacent the operators station 17. Byoperation of the control reel 68, the operator may raise or lower thedistal end of support frame 60, and thereby tilt the X-ray tube 64 tochange the angle of incidence of the beam with respect to the specimen.

A rack gear 69 is disposed between and parallel to the arms 61 and inengagement with a drive motor 70 which is mounted on the holder 63.Operation of the drive motor 70 therefore causes the holder 63 to bemoved along the arms 61 and carry the X-ray tube 64 toward or away fromthe specimen tunnel 11, thus regulating the distance between thespecimen and the radiation source. Power and control leads to the X-raytube 64 and the drive motor 70 are carried by the conduit 71 to theirrespective control panels 72 and 73 on the face wall 15 adjacent theoperators. station 17.

To produce an image from the beam of radiation after it has interceptedthe specimen, a fluorescent screen 75 (see Figure 3) is provided ontheopposite side of the specimen tunnel 11 [from the opening 21a anddisposed in the path of the beam, which enters from the radiation tunnel12. The screen 75 is carried by a yoke 76 which is pivotally mounted tothe inside of the access door 16. The pivotal mounting of the yoke 76 isurged by a spring 77 (see Figures 8 and 9) to normally carry the screen75 inwardly toward the specimen. To control the amount of inwardmovement, a cable 78 is attached to the yoke 76 and connected throughthe door 16 to a control lever 79 on the outside of the-door. Bymovement of control lever 79, the movement of yoke 76 may be controlled6 and the screen 75 positioned as close to the specimen, as desired.

The screen 75 is pivotally mounted on pintles 80 at the free end of theyoke 76 so that it may be adjusted about a vertical axis to differentangles with respect to the specimen. Thus, if the specimen has an unevensurface, the screen may be adjusted to the particular portion to beviewed. The access door 16 is convenient for making these adjustments.

To provide means by which the operator can view the screen 75, viewingapparatus is incorporated into access door 16. For this purpose, theaccess door 16 has an aperture 81 therethrough which is aligned with thescreen 75 and covered by a sliding plate 82. The plate 82 slideslongitudinally with respect to the specimen tunnel in channels 83provided on access door 16 and has as part of it an aperture similar tothe door aperture 81 which is covered by a viewing window 84 of leadglass or other suitable transparent material which is transparent tolight but impervious to the radiation used, and an electronic imageintensifier 85. The electronic image intensifier 85 can be any ofseveral types, presently on the market, such as those manufactured byWestinghouse Electric Company, General Electric Company, PhilipsElectronics Corp, Bendix, and others.

The sliding plate 82 may be moved by the operator to position either thewindow 84 or the image intensifier 85 over the aperture 81. Photographicequipment may also be positioned on plate 82 and slid over the aperture81 to record the image of the specimen photographically.

To perform the inspection of a part or assembly, the apparatus operatesas follows: the specimen is inserted into the specimen tunnel 11 of thehousing 10 through the specimen portal 19 and securely mounted on thespecimen support 24 by means of the fixture 56 and clamps57. All of thedoors allowing access to the interior of the housing are interlockedwith the X-ray tube source of power, so that power may not be appliedwhen they are open. This prevents any injury to operating personnel byharmful radiation through their inadvertence.

When all of the access doors have been closed, including the specimenportal 19, the operator actuates the X-ray tube 64 by means of thecontrol panel 72 at the operators station 17.

The sliding plate 82 is then regulated by the operator so that the beammay be viewed either by the fluorescent screen 75 and window 84 or bythe image intensifier 85. The screen 75, of course, fluoresces whenactivated by the beam of radiation.

The specimen support 24 is then actuated to move the specimen intointersection with the X-ray beam. By controlling the movement of thevertical and horizontal carriages 25 and 26 through the control panel55, the specimen is moved about in front of the beam until its entirearea has been scanned and inspected by the operator.

If better resolution of the image on fluorescent screen 75 is desired,the X-ray tube 64 can be backed away from the specimen by activating'thedrive motor 70 from the control panel 73, and driving the bracket 83rearward on the support frame arms 61 so that the individual rays of thebeam will be more nearly parallel when they strike the specimen. It willbe understood, of course, that the length of the radiation tunnel 12 andthe support frame 60 may be as long as necessary to give sufiicientspacing for the resolution desired in a particular application. Thus,this apparatus, in utilizing a horizontally directed radiation beam, hasa significant advantage over apparatus having a vertically directedbeam, since, with a horizontally directed beam, the operators positionis not aiiected by an increased spacing between the specimen and theX-ray source, no matter how great this increase is. The onlymodification necessary is the elongation of radiation tunnel 12 andsupport frame 60.

As a further means of improving the image, the spam is again positionedadjacent the specimen portal.

ing between the specimen and the screen 75 may be adjusted by regulationof the control lever 79 on the access door 16. If positioned closer tothe specimen, the screen image will be brighter, the resolution better,and the magnification of the image less. If positioned further away, themagnification of the image will be increased, but the intensity will beless and the resolution poorer.

The intensity of the image will be affected, of course, by the spacingbetween the X-ray tube and the screen, greater spacing giving lessintensity. Generally, therefore, for detailed analysis of a portion ofthe specimen, the screen will be moved as close as possible to thespecimen and the X-ray tube spaced as far away as possible, to the pointwhere the intensity is still sufiicient to give a good image. Thepositioning of the source of radiation is, of necessity, a compromise,since the best resolution will result when the source is positioned asclose as possible to infinity, but if the source is positioned too farfrom the screen, the intensity of the beam striking the screen is notsufficient to make the image visible. Use of the electronic imageintensifier can be of considerable advantage here, since it may be usedto detect images having far less intensity than would be needed ifviewed with the naked eye.

For general scanning, where resolution is not so important, the screenmay be positioned farther away from the specimen to give a slightlymagnified presentation and the X-ray source brought closer to thespecimen to increase the intensity.

If it is desirable to view the specimen with the radiation beam strikingit at a different angle of incidence, operation of the control reel 68will raise or lower the distal end of the frame 60 through cable 66, andthus tilt the X-ray tube 64 and vary the angle of incidence. Since flawsand defects often show up much more plainly at one angle of incidencethan at another, this tilting feature makes analysis much morecomprehensive.

After the specimen has been moved about by specimen support 24 andcompletely scanned by the beam, it Power to the X-ray tube 64 is thenshut off and the inspected specimen is replaced by a new one forrepetition of the above-described operation. Though the specimens areplaced on the specimen support 24 individually in this embodiment, itwill be appreciated that by minor changes in the structure, the specimensupport could be arranged to carry specimens into and out of theapparatus on an assembly-line basis.

From the above description of the construction and operation of apreferred embodiment of the invention, it will be apparent that thisapparatus provides significant advantages not heretofore available. Thehorizontally disposed radiation beam and T-shaped housing form aconstruction which allows substantial variations to be made in thespacing between the X-ray source and the specimen, to improve imageresolution, without necessitating any major changes in the equipment orinconvenient respositioning of the operator.

Also, large parts and assemblies may be inspected by the apparatuswithout the use of excessive floor space and with adequate protectionfor the operator. In fact, because of the power-operated specimensupport and the X-ray tube and screen mounting arrangements, theoperator may control the apparatus and perform a very complete andcomprehensive inspection without ever leaving his convenient operatingstation 17 in front of the specimen tunnel 11.

With this apparatus, the operator, without leaving the operatingstation, may move the specimen to any desired position before the beam;vary the spacing between X-ray source and the specimen, and between thescreen and the specimen to give the desired combination ofmagnification, intensity and resolution; and tilt the X-ray source togive the desired angle of incidence. Furthermore, the operator may viewthe image, either directly 8 by the screen and window 83 or in anintensified version through the image intensifier 85, and, if desired,may make a photographic record of the image.

All of these features have been incorporated by this invention into acompact, self-contained apparatus which is especially adapted toindustrial use because of its safety, economy and durability.

While the preferred embodiment of my invention shown in the drawings anddescribed in this specification is fully capable of performing theobjects and advantages herein stated, it should be understood that I donot mean to limit myself to the details herein specified, except asdefined in the appended claims.

I claim:

1. Fluoroscopic inspection apparatus comprising: a housing having wallsof material substantially impenetrable by radiation, said housing havinga sliding panel in one wall thereof, said panel having a transparentportion, a radiation source within said housing for emitting a generallyhorizontal beam of penetrating radiation toward said one wall; supportmeans positioned adjacent said radiation source and in general alignmentwith said beam for positioning a specimen in said beam, said supportmeans having carriages capable of moving said specimen both verticallyand horizontally, simultaneously, in a plane substantially perpendicularto and intersecting said beam; image-producing means for producing animage when activated by said beam, said image-producing means beingpositioned to intercept said beam after passing through said specimen;an image intensifier device mouned on said sliding panel, whereby saidpanel can be selectively positioned to align said transparent portion orsaid image intensifier with the specimen; and support means for saidsource operable from the exterior of said housing to vary the spacingbetween said source and the specimen, and for tilting the source to varythe angle of incidence of the beam with respect to the specimen.

2. Fluoroscopic inspection apparatus comprising: a radiation source foremitting a beam of penetrating radiation; support means positionedadjacent said radiation source and in general alignment with said beamfor positioning a specimen in said beam; means coacting with saidsupport means for moving said specimen in a plane substantiallyperpendicular to and intersecting said beam to scan said specimen;image-producing means for pro ducing an image when acitvated by saidbeam, said image-producing means being positioned to intercept said beamafter passing through said specimen; a housing of material substantiallyimpenetrable by said radiation and enclosing said radiation source andsupport means to shield personnel from said radiation; movable mountingmeans for supporting said radiation source and said housing for movementtoward and away from said support means to vary the spacing between saidradiation source and said specimen; and means supporting said mountingmeans for tiltable movement of said source to change the angle ofincidence of said beam on said specimen.

3. Fluoroscopic apparatus comprising: a radiation source for emitting abeam of penetrating radiation; support means positioned adjacent saidradiation source and generally aligned with said beam for supporting thespecimen in said beam; carriage means on said support means for movingsaid specimen in a plane substantially perpendicular to and intersectingsaid beam to scan said specimen; image-producing means for producing animage when activated by said beam, said image-producing means beingpositioned to intercept said beam after passing through said specimen; ahousing of material substantially impenetrable by said radiation andenclosing said radiation source, support means and image-producing meansto shield personnel from said radiation; first mounting means formounting said image-producing means in said housing, said first mountingmeans being pivotally movable with respect to said housing for varyingspacing between said support means and said image-producing means;second mounting means for movably supporting said radiation source insaid housing for movement toward and away from said support means tovary the spacing between said radiation source and said specimen; andmeans supporting said mounting means for tiltable movement of saidsource to change the angle of incidence of said beam on said specimen.

4. Fluoroscopic inspection apparatus comprising: a radiation source foremitting a generally horizontal beam of penetrating radiation; supportmeans positioned adjacent said radiation source and in general alignmentwith said beam for positioning a specimen in said beam, said supportmeans having carriages capable of moving said specimen both verticallyand horizontally, simultaneously, in a plane substantially perpendicularto and intersecting said beam; image-producing means for producing animage when activated by said beam, said image-producing means beingpositioned in said beam after said specimen; shielding means forprotecting personnel from said radiation; power-operated drive means fordriving said support means, said drive means being operable from aremote station; an elongated support frame mounted adjacent said supportmeans for supporting said radiation source; a holder carrying saidradiation source with said beam directly toward said support means, saidholder being mounted on said support frame for longitudinal movementthereon to carry said source toward and away from said support means;power-operated drive means for moving said holder on said support frame,said drive means being operable from a remote station; and a support armon the opposite side of said support means from said support frame andsupporting said image-producing means in said beam as aforesaid.

References Cited in the file of this patent UNITED STATES PATENTS2,683,812 Schneeman July 13, 1954 2,767,322 Daly Oct. 16, 1956 202,813,201 Wiebe Nov. 12, 1957

